Patent GB-800379-A (GB)
Title: Improvements in or relating to steering mechanism for articulated road vehicles
IPC: B62D13/04
Filed: 1954-12-07
Abstract: 800,379. Articulated vehicles; steering trailers. MULTI-STEERING CO., Ltd., and VIAZEMSKY, S. V. C., PRINCE. Dec. 1955 [Dec. 7, 1954], No. 35472/54. Classes 79(3) and 79(5) A steering mechanism for an articulated road vehicle comprises means actuated by the articular movement between two parts of the vehicle for operating a steering transmission for the trailer wheels, and means for rendering the first means inoperative on the wheels of the trailer after a predetermined articular movement between the two parts of the vehicle, whereby continued articular movement may take place 'without transmitting steering movement to the trailer wheels. In the constructions shown in Figs. 2 and 3, there is an automatically - engaging connection 22 between the forward ends 20 of the trailer, and a turntable 17, 18, carried by the tractor. A. cross member 33 is normally rotationally fixed relative to a pin rigid with the tractor by a dog clutch 34 held in engagement by a spring 37. Each of the other ends of the cross member 33 are connected by a linkage 46, 32, 49 to a respective end of a cross beam 30 pivotally mounted at the rear of the trailer. An arm 29 rigid with the beam 30 is connected by a link 28 to a conventional steering mechanism for the trailer wheels 15. Each linkage 46, 32, 49 includes a universal joint 45 and a lost-motion connection 48, Figs. 4 and 5 (not shown). The member 33 is rigid with an arm 40 which is adapted to engage a cam member 39 rigid with the trailer. After a predetermined degree of articular movement between the tractor and trailer, the cam 39 forces the arm 40 downwardly against the action of the spring 37 to disengage the dog clutch 34. This disconnects the steering mechanism from the tractor, and the beam 30 is forced in one direction or the other by a toggle mechanism 42 to engage one or other of limit stops 41, 41<SP>1</SP>. A control may be provided for the driver of the tractor to override the clutch 34. In the construction shown in Fig. 7, the forward ends of the links 46 are connected to the extremities of a cross member 55 which at its centre is pivotally mounted on the forward end of the trailer frame. Coaxially with its mounting the arm 55 carries a bearing block 58 in which is slidable a rod 59, the forward end of which is pivotally connected to a member 61. The latter has a snap action connection in a socket 63 rigid with the tractor adjacent the axis of the turntable 17, 18. The rod 59 may alternatively be rigid with the arm 55, in which case it is slidable in a guide rotatable on the member 61. In operation, articulating movement between the tractor and trailer results in the rod 59 causing the arm 55 to rotate until a point is reached when the rod 59 can slide freely through the bearing block 58 and no further rotation of the arm 55 takes place. A clutch mechanism similar to the dog clutch 34 of Figs. 2 and 3, may also be employed. Mechanism is described, by means of which the driven may lock the wheels 15 against steering movement, when they are in their normal straight ahead position and/or when they are in their full deflected position. This mechanism may be interconnected with the control for overriding the clutch 34. A spring detent may be provided between the member 61 and the forward end of the trailer frame to prevent the member 61 from swinging about when it has been uncoupled from the socket 63.